Question: What is the difference between physical and logical addressing? When would I use one over the other?
Answer: Physical addressing uses a 64-bit address to represent each node on the powerline. Every PLC device has a unique 64-bit address. This is useful when initializing a system because the nodes do not have unique logical addresses on power up. However, it is inefficient to use physical addressing all the time because it requires 16 bytes when transmitting a packet from a physical source address to a physical destination address. This will increase latency and reduce throughput.
Logical addressing uses either an 8-bit or 16-bit (extended) address to represent each node on the Powerline. This addressing mode uses only 2-4 bytes for transmitting a packet and therefore, has a much lower latency and higher throughput.
When there are multiple independent networks sharing the same Powerline grid, it is important to bind the nodes (e.g. slave host only processes messages from the master’s source address, or the nodes use a unique key in the payload or the additional byte in the extended address to define the network).
